Surveillance cameras are extremely well known and used to help deter theft, crime and the like.
It is also well known to store as a sequence of images on some type of medium the event that the surveillance camera is recording. Conventionally, such storage has been done using VCR's, and storing the images obtained from the event on a tape. Such a storage medium, however, has the disadvantage of requiring the frequent removal of and old tape and insertion of a new tape every few hours, which, when many cameras are being used, is a time consuming and tedious process. Further disadvantages occur since it is difficult to authenticate the recording stored on the tape. Still further, as a result of tapes degrading over time, as well as then typically being played back on a player different from that which recorded the tape, the resulting sequence of images may not be clear.
The storage of images obtained from such events in digital form has also been contemplated. In such a system, images from the event recorded by the camera are converted to digital form, and have been compressed in some manner, such as using the known MPEG format. To date, however, such systems have not proved feasible for a variety of reasons. In situations requiring many cameras simultaneously the bandwidth required as a result of all of the cameras being used has prevented storage of images over a period of time that is long enough and which has sufficient resolution to decrease the overall cost of information storage to a point that digital storage is economical.
One conventional approach to this problem is to begin recording when movement of some type is detected, so that otherwise still images are not continuously recorded, thus reducing the storage requirements necessary for operation of the system. Usage of such event initiation indicators in this manner introduce problems of their own, such as, for example, not having a continuous record.
An improved surveillance system is thus desirable.